Embodiments disclosed herein relate to processes for the preparation of toner particles. More particularly, embodiments disclosed herein relate to processes that control the coalescence of latex particles in the formation of toner particles.
High temperatures (about 80° C. or more) drive the coalescence of aggregated latex particles into contiguous toner particles in conventional aggregation/coalescence processes. However, employing high temperatures may be energy intensive, lead to long temperature ramp-up times following aggregation, and may cause excessive fouling in reactors and pH systems. Aggressive cleaning of all processing equipment and pH systems may be required due to such fouling. Moreover, high coalescence temperatures can also cause coarse particle growth, a problem that can be exacerbated by temperature spikes from the heating jacket in conventional cascade controlled heating systems.
Cascade controlled heating typically involves the direct monitoring of reaction temperature in conjunction with a feedback temperature controller used to adjust the temperature of a heating element, such as a heating jacket, to meet the demands of the targeted reaction temperature. Temperature spikes may arise when the feedback controller adjusts the power to the heating element in response to a need for the reaction mixture to be increased up to the target temperature. A nominal delay in attaining the requisite reaction temperature, or other circumstances, may cause the feedback controller to signal the need for more heat, ultimately overheating the heating element and causing the reaction temperature to overshoot the target temperature.